The present invention relates to a lock device capable of opening a door, even in the case when a dead bolt is in a locked position, without using a key by releasing the locking condition of a trigger bolt from a door frame side by means of remote control.
Conventionally, in a lock device of a door comprising a dead bolt, a latch bolt, and a trigger bolt, the trigger bolt of the lock device is installed for the purpose of locking the latch bolt not the dead bolt. For this reason, in the case of the lock device having means for releasing the trigger bolt from the door frame side by remote control in the control room, when the door is closed in a state of temporary locking with the dead bolt unlocked, the locking condition of the trigger bolt for fixing the latch bolt can be released from the door frame side by remote control from the control room, and then a visitor can draw the latch bolt by turning the knob of the door and can open the door.
In the afore-mentioned conventional lock device, the trigger bolt is locked on the latch bolt. Therefore, in a state of locking the dead bolt regularly, when a visitor comes to the door and the manager of the control room releases the locking condition of the trigger bolt from the door frame side by remote control from the control room, the visitor can turn the knob from the external side and can draw in the latch bolt, but he cannot draw in the dead bolt. Consequently, there remains a problem to be settled that the door cannot be opened from the external side without employing the key for opening it.
For this reason, the visitor cannot open the door even though the trigger bolt is released by remote control in a state of locking the lock device regularly. Therefore, the manager of the control room has to go to the door and release the dead bolt. It is an inconvenient problem to be settled.